A Pack of Lies
by Esther Kirkland
Summary: An unexpected visitor to the Shack turns life upside down for the Pines family - but is this newcomer everything he says? Or is there something more sinister going on? And can Stan protect the secrets he's held onto for so long? This is an adventure fic, no real ships, no real theories - just adventure. Takes place shortly before Not What He Seems, but not spoilery.
1. Chapter 1

Ok, so this one happens just before Not What He Seems. I had originally intended to put it in the middle of season one, somewhere around Irrational Treasure (which is why, if you're paying attention, you'll notice that Waddles doesn't make any appearances.) However, near the end I realized that there were some questions raised that flowed better with the plotline of the show if it happened right before NWHS. So… yeah, that's what happened. Again, this is simply an adventure fic, hopefully mostly in the same tone as an actual episode of Gravity Falls, though the climactic scene near the end is perhaps a little more intense than GF usually gets. But more on that later. Please enjoy, and do take a second or two to leave a comment letting me know what you think. :D

* * *

1.

Dipper tossed the latest issue of the Gravity Falls Gossiper across the floor and flopped back on the rug.

"Ugh," he sighed. "I don't like being famous."

Mabel looked up from painting Waddle's toenails and glanced at the front page of the paper. "Mystery Shack Hero Spotted Eating Boogers," she read. "Ew, Dipper."

"It's a lie! Yellow press! I had something stuck in my teeth, not my nose."

"I don't know, Dip," Mabel picked up the paper and examined the grainy, black-and-white photo. "The evidence is pretty compelling."

"Give me that." Dipper snatched the paper away and tore off the front page, which he then wadded into a ball and tossed in the corner.

"They're just looking for stuff to print," Mabel reassured him. Then she snorted. "Ya gotta admit though – it's pretty funny."

Dipper flopped back again, but the corner of his mouth turned up in a tiny smirk. "Ok. Maybe it's a little bit funny."

The truth was, he didn't really mind being famous – or as close to famous as someone could get in Gravity Falls. Someone had managed to get a pretty epic shot of him catching that giant bat a few weeks ago, and after the little incident up at the Northwest Mansion with Pacifica's family ghost… Anyway, the long and short of it was that Toby Determined was now convinced that Dipper Pines was his ticket to the next breaking story – or at least to Shandra Jimenez's favor. But the paparazzi-stalking thing was getting a little old.

Outside, the sound of a car door slamming announced the arrival of another tourist.

"Ten bucks says old people!" Dipper jumped to his feet and dashed for the window.

"Family with four kids! And a duck!" Nail polish went flying as Mabel raced to get there first.

"A duck? Seriously, Mabel—"

They reached the window at the same time, and Dipper looked out to see a man, maybe a little younger than the twins' parents, walking toward the shack.

"Both wrong," Mabel said. "Good thing too – I'm broke."

"Wonder who that guy is?" Dipper squinted. "He doesn't look like a tourist."

He didn't look like much of anything, really. Generic brown hair, generic blue polo shirt, generic jeans – even his car was a generic green sedan. The stranger's only defining feature was the expensive-looking briefcase he carried and the look of anxious determination on his face.  
Then the twins lost sight of him under the edge of the roof.

Mabel rescued her jar of nail polish and blew one last time on Waddles' drying nails. "Wanna go see what he's up to?"

"Do you even have to ask?"

The twins pounded down the stairs just as the doorbell rang. "We got it, Stan!" Dipper shouted, throwing open the door. "Hi there, and welcome to the—"  
The stranger stepped inside, brushing past Dipper and Mabel as if they weren't even there.

"—Mystery Shack?" Dipper raised an eyebrow at Mabel. She shrugged, and scrambled to step in front of the intruder.

"If you're here for a tour, visitors are supposed to come in through the gift shop—" she started, but the stranger just held up his briefcase as if it were a badge.

"Visitors are supposed to, yes," he said. "But I'm not a visitor. My name is Sheldon Pines and…" he straightened his shoulders. "And I live here."


	2. Chapter 2

**A/N:** Hey, all - sorry for the delay. What with the holidays, and my sibs and I just signed a lease on a house, this week was rather busy and I didn't get online at all on Friday. I'm here now, though. 3

Have a new chapter, and let me just say while I'm here that I plan to keep writing these adventures after Gravity Falls ends. They'll continue to fit in the gaps between episodes, and hopefully feel just like extra stories that the wonderful Hirsch and his team didn't have time to tell us about.

Anyway, without further ado:

Chapter Two.

* * *

2.

"…And then Grunkle Stan came in and sent us outside and we haven't seen them since." Dipper waved his arms over his head. " _Anything_ could be happening in there!"

"Whoa, calm down, Dipper," Wendy said from her lounging seat on a log. She twiddled a small stick between here fingers and pointed it at Mabel thoughtfully. "Did he look like a lawyer?"

Mabel shook her head. "No – and besides. He said his name was Sheldon Pines. _Pines._ " She was kneeling on the ground with an arm slung around Waddle's porky shoulders, and now she scratched the pig's ears absently. "Which is totally weird since _our_ last name is Pines, and Grunkle _Stan's_ last name is Pines but—"

"But we've never heard of this guy," Dipper finished. "I can't think of how he's related to us – much less how he thinks he's supposed to _live_ here."

Just then, the front door of the house opened, and the mystery man stepped out, followed by an exhausted-looking Stan. They shook hands, and the stranger walked over to his car, got in, and drove away – all without so much as a glance at the kids.

"Grunkle Stan – what was that?" Dipper demanded, running across the yard to meet his uncle. Mabel and Wendy – and Waddles, naturally – followed at a more reasonable pace.

"I…don't want to talk about it right now," Stan said. He took off his glasses and rubbed at the bridge of his nose. "I'm, ah... I'm shutting down the Shack for the rest of the day. You kids go… vandalize public property or something."

And with that, he disappeared inside the house, shutting the door in Dipper's face.

Dipper stared at the wood in front of his nose for a second, then spun to face his sister and Wendy. "What just happened?"

Mabel looked anxious. "I don't know," she said slowly. "But I don't think it was good."

Even Wendy's face was creased in concern. "I don't know what's going on with Stan," she said. "But we may be able to find out. Come on, let's head to the library."

"The library?" Dipper started to follow her, but paused, confused. "What's at the library?"

"Free internet, man." Wendy hopped onto her bike and snapped on a helmet. "Coming, or what?"

* * *

The Gravity Falls library was a small and rather dark building, and most of the books had copyright dates from the sixties or before. But a state grant a few years back had paid for several computers and an internet connection that was only slightly buggy – though Dipper suspected some supernatural pest was responsible for most of the issues.

"Did you see that?" he ducked his head under the desk, just in time to see some dimly-sparkling creature skitter under the wainscoting.

"Dipper, focus." Mabel was perched on a chair, lurking over Wendy's shoulder. "We're just getting to the good stuff. Is that a trout?"

Wendy squinted at the screen, the blue light reflecting off her face. "I think it's a carp."

Dipper sat back in his chair and sighed. "Guys, we've been surfing this guy's Myface page for an hour, and we've learned nothing except that he likes to fish, posts way too many one-does-not-simply memes, and has apparently no friends because no one ever likes or comments on his updates."

Wendy kept scrolling, but he could tell she was losing her enthusiasm. "I was sure we'd find _something_ in here," she said. "Maybe if I sent him a stalk request…"

"Wait!" Mabel leaped to her feet. "Scroll back up a bit!"

Wendy returned to the last text post. "'Today I found out that I'm adopted,'" she read aloud. "So? Besides being an obvious cry for attention, what does that have to do with—"

Dipper's eyes widened. "No, wait. Wendy – she's right. If this guy's adopted, but he shares our last name, maybe he thinks that—"

* * *

"—I'm his father." Stan plonked a can of soda in front of each of the twins, and looked at Wendy. "Are you still here?"

"Hey, I want to know about your deep, shady past too!" Wendy said.

"Out." Stan pointed at the door. "Before I fire you."

Wendy rolled her eyes, but turned to go.

"We'll tell you everything tomorrow," Dipper called after her.

"Whatever, man."

The front door swung shut behind her.

"Grunkle Stan," Mabel chided. "That was rude."

The older man shrugged and swigged his drink. "This is family business, kid. You can tell her whatever you want later."

Dipper was turning his chilled cola in his hands, watching the way the condensation beaded on the metal. "You've got… a son?" he asked.

Grunkle Stan sighed and sat in his chair.

"His name is Sheldon," he began. "Sheldon Wheatley until a few months ago. That's when his parents told him he was adopted – he's got some kind of nut allergy and had to get medical records for his birth parents. His birth mom died a few years back, but in the process he discovered his dad's name." Grunkle Stan looked at his soda can as if it held the secrets of the universe. "Stanford Pines."

"So he's, what," Mabel squinched her face. "Our cousin? Great cousin?"

"Second cousin," Dipper said. " _If_ he's telling the truth."

Grunkle Stan shook his head. "He's got a birth certificate," he said simply. "And it says Stanford Pines on it. And someone named... Debbie Palmer."

"Were you in _love_?" Mabel gasped.

Grunkle Stan looked away. "Look, kids," he said. "I haven't exactly lived the most—that is, what I'm trying to say is, I've made a lot of mistakes. And met a lot of people. And done a lot of things I'm not that proud of." He crunched the empty soda can. "I don't remember a Debbie, but that doesn't mean there wasn't one."

There was something in his tone that struck Dipper as odd – a pain, maybe, that went beyond the death of a woman he couldn't remember and the appearance of a son he'd never known existed. But before he could figure out a way to ask about it, the older man stood.

"He's coming back in the morning," Grunkle Stan announced. "He'll be moving into the guest room, since you both decided to go back to the attic."

"He'll be _living_ here?" Dipper exclaimed. "In the Shack?"

Grunkle Stan shrugged. "It's the least I can do," he said. "Figure I owe the kid something."

He tossed his crumpled can in the garbage and disappeared up the stairs to his room, leaving Dipper and Mabel seated at the kitchen table, the yellow glow of the light above them the Shack's only illumination.

Mabel sighed and rested her chin on her hand. "This is weird," she said. "I don't want to share the Shack with someone new. Especially not trout-face-Sheldon."

"It was a carp," Dipper replied automatically. He stood and took his unopened soda to the refrigerator. "Personally, I have some doubts about this Sheldon guy. I say we keep digging and find out what he's really up to."


	3. Chapter 3

**A/N:** Hey, guys, sorry for the late update. With holidays messing up my week's schedule, I didn't have access to the internet on Friday. Hopefully we'll get back to normal here soon, but until then, I'll do my best to post as close to Friday as possible. Again, sorry for the wait.

If I haven't alienated you too much, leave me a note to say what you liked/didn't about this chapter. Look forward to hearing from you!

~Essie

(0.o)

* * *

3.

The next few days were nothing short of horrible at the Mystery Shack. That is – they were awkward, and weird, and everywhere he turned, Dipper felt like he was in Sheldon's way.

The stranger had moved into the guest room – now divested of anything that might cause body-switching, teleportation, spontaneous human combustion, or anything else supernatural – and spent his days wandering the Shack on feet as silent as a cat's. Dipper was losing track of how many times he had turned around to find Sheldon standing behind him, or looked up from a book to realize that the man had made himself at home on the couch opposite without a sound.

"Thirty-three!" he ranted to Mabel as they walked through the woods on the way to Wendy's house. "Thirty-three times he's snuck up on me!"

"He's a ghost," was Mabel's reply. "He's not Stan's son, he's Stan's great-grandfather here to _steal our souls_." She made her voice deep and creepy on the last three words, waving her arms in a spooky manner.

"That's not funny." Dipper thought back to the category-ten ghost at the Northwest Mansion, and grimaced. "And besides, I don't think he's a ghost. He's too… normal."

That was true. Aside from his near-silent stalking around the Shack, Sheldon was disconcertingly normal. He ate ham and cheese sandwiches for lunch every day. Oatmeal with a dash of cinnamon for breakfast. He knocked at the bathroom door. He didn't watch the Gravity Falls news, but checked the national feeds on his smartphone.

"He can't be Stan's son," Dipper declared. "There is no way that someone that normal could share genes with our great uncle."

"Well if he's not Stan's son," Mabel asked, "Who could he be?" She kicked at a rock and watched it sail thirty feet before smacking dead center into the trunk of an oak tree. "Ha – ten points."

"I don't know," Dipper said. He pounded a fist into the opposite palm. "But we're going to find out."

"What I really want to know is," Mabel continued, "If he's not Stan's son, why is he pretending to be? It's not like Stan is some millionaire who would leave him lots of money or something."

"True." Dipper looked up at the cloudless blue sky peering through the gaps in the canopy of leaves above them. "In order to find out who this guy is, we've got to figure out what he wants – why he's here."

"And soon," Mabel added. She kicked another rock with deadly accuracy, and watched it fly through the air to hit the same tree as before. "I'm getting really tired of Sheldon Liar-Pants Not-Pines."

* * *

Finding out what Sheldon Not-Pines wanted turned out to be easier said than done.

"So…" Dipper said over breakfast. "What did you say your job was?"

Sheldon didn't even look up from his oatmeal. "I didn't."

Dipper glanced at Mabel, who shrugged. No one said anything for the rest of the meal.

When Sheldon went out later that day, driving away in his green sedan on a mission to buy sandwich meat, they snuck into his room.

"Mabel, this guy sorts his socks by color and size," Dipper said, sliding the dresser drawer shut.

She sighed and looked up from the open suitcase on the floor. "Nothing in here but some old sciency magazines and half a tube of toothpaste."

"Old magazines?" Dipper crouched next to her and pulled them out, flipping through the wrinkled pages. "Wow, these are from the eighties. I wonder why he's carrying these around – ha, check this out." He pointed at a page with a blurry image of the moon and the earth as seen from space, two crescents of dim light in a sea of black. " _The Earth and the moon photographed together for the first time by NASA's Voyager 1_ ," he read. "Cool."

"But useless," Mabel said, sitting back. "Unless he's here trying to steal the moon or something." She perked up for a second. "You don't think—"

"I highly doubt he's here to steal the moon, Mabel."

"Right. I knew that."

Dipper turned the page in the magazine and glanced at the next page. He froze. "Oh my gosh – Mabel," he breathed. "Look at this!"

She peered over his shoulder. _"Modified Dimensional-Threshold Probability Theorem in Relation to Residual Outflow._ So?"

"Look at the author."

Mabel's eyes widened. " _Stanford Pines_!?" she exclaimed.

Dipper was skimming through the text of the article. "It's all about the possibility of residue from another dimension leaking into ours," he summarized. "All of it sounds pretty theoretical but… But it also sounds like he could be talking about Gravity Falls. There's some stuff about mythical creatures in here – nothing substantial, just the suggestion that sightings might be caused by other dimensions seeping into ours." He looked up at his sister. "Mabel, it sounds just like the journals! What if…what if _Stan_ is the author?"

Mabel ran a finger down the solid block of text. "There's a lot of complicated stuff in here, Dip-dop," she said with a frown. "Some of these words are really long. I don't know if Grunkle Stan has this kind of science-nerdy stuff in him."

Dipper turned a page. "It's pretty technical," he agreed reluctantly. "I guess it doesn't really sound like Stan. But I doubt it's a coincidence that Sheldon has this – but why hasn't he said anything about it?"

From outside, there came the sound of a car door slamming.

"He's home!" Mabel leaped to her feet. "We gotta get out of here!"

They replaced the magazines in the suitcase and dashed out of the room – at the last second, Dipper spun back and flipped out the light. By the time Sheldon reached the house, the twins were sprawled on the couch, a rerun of _Into the Unknown_ flickering on their apparently-vegged-out faces.

"Hey, Sheldon," Mabel said as the man entered. "Want to watch with us?"

Sheldon gave a wan smile that didn't reach his eyes. "No thanks, Megan."

"Mabel."

"Right. Have you seen your great uncle?"

Dipper pointed with the remote. "He's in the gift shop. A group came in while you were gone."

Sheldon vanished down the hall in the direction of the gift shop, and the twins gasped – breathing hard from running down to the living room, and even harder from having to hold in their breathlessness while Sheldon stood there.

"I really, really don't like him," Dipper muttered. "He called me Dylan twice yesterday."

"I'm pretty sure he thinks I'm five." Mabel tossed an abandoned popcorn kernel across the room. "He gave me the doll prize from the cereal box."

"But you wanted the doll – that's why we got that cereal."

"That's beside the point!" Mabel flopped her head back dramatically. "It's one thing if I _say_ I want something, it's another if someone _assumes_ I want it."

"I'm a hundred-percent certain that something is up with this guy," Dipper said firmly. "Even if he _is_ Stan's son, I don't believe for a second he's just here for a family reunion. He wants something else. Maybe something connected to that article."

"You think he's after something weird in Gravity Falls? Like the gnomes or Gideon's weird amulet thingy?"

Dipper shrugged, his gaze locked on the television – currently a commercial for bunion cream – but his attention obviously elsewhere. "I have no clue," he sighed. "But we've got to find out."

Just then, Grunkle Stan poked his head around the door to the living room. "Sheldon's not in here, is he?" he asked.

"No – we just sent him to the gift shop looking for you."

Stan visibly winced. "Right. Right – I should probably go find him," he said. But he didn't move.

"Is something wrong?" Mabel asked.

Stan shrugged. "Nah – no. I mean – it's a little weird and I'm not used to the idea of having a kid but…" he scratched at his nose. "No, nothing's wrong."

He retreated, heading back toward the gift shop.

"He's lying," Mabel declared. "He's not happy about Sheldon any more than we are."

Dipper nodded. "We're going to get to the bottom of this." The show returned from commercial. "…right after this episode."


	4. Chapter 4

4.

Operation Figure Out Sheldon Not-Pines got off to a rocky start the next day.

Literally.

Dipper lugged the burlap sack full of stones up the front porch steps, grunting as he tugged it over the lip of the top stair.

"This is the worst idea ever," he said, panting. "No one is going to buy these."

They'd been out in the woods all morning finding the rocks – anything fist-sized was acceptable to Grunkle Stan. "It's like growing our own money!" he'd exclaimed, hefting a limestone specimen.

Now Stan pointed at the wooden barrel in the corner of the gift shop. "Sure they will, as soon as I put up this sign." He held up a painted card that read _Genuine Mystery Rocks - $5_. "We'll tell folks they're from the forest – which they are – and that they're mysterious."

"Why are they mysterious?" Mabel was perched on the counter, her feet swinging against the side.

"That's the mystery." Grunkle Stan helped Dipper lift the sack and dump the rocks into the barrel. They thundered in with a sound like… well, like a load of rocks in a wooden barrel.

"Great," Stan said, shaking out the sack. "Only three more sacks to go."

"What's that noise?"

The three Pines turned to see Sheldon standing in the doorway that connected the shop and the house.

"Merchandise," Grunkle Stan replied, as if that explained everything.

Sheldon grimaced, and poked a bobble-headed Sasquatch figure on the shelf beside the door. It shook its head cheerfully. "Stan – can I talk to you?" he glanced at the twins. "In private?"

Stan looked uncomfortable. "Uh, sure. Whatever you need. Let's, uh – we'll go in my office. Dipper, keep hauling in those rocks."

He followed Sheldon out of the gift shop.

Dipper flexed sore hands, and headed back out to grab another sack from the back of the golf cart.

"Dipper!"

He looked up to see Wendy biking up the trail to the Shack. She waved a hand at him. "Get Mabel and your bikes!"

Dipper pointed at the bulging sacks of rocks in the golf cart. "I've got to get these inside first."

Sliding to a stop, Wendy leaped off her bike and hefted a sack of rocks in each hand. "Oof," she grunted. "Great – I'll help. Then you two need to come with me."

Together – Wendy taking two bags to Dipper's one – they lugged the rocks into the gift shop and dumped them into the barrel.

"What's so important?" Mabel asked, hopping down from the counter.

Wendy just grinned. "Seriously, man – you gotta wait for the reveal. I spent all night working on this."

"We'll grab our bikes," Dipper said, tossing the last empty sack in the corner. "Soos'll be here in a few minutes to open the shop."

* * *

Soon, they were back at the library. The librarian, a roundish woman with thick glasses and a pin on her lanyard that said 'Keep Calm and Read On,' gave them suspicious looks as they came in. Probably not too many kids came into the library in the summer.

But Wendy headed straight back to the computers and logged on, pulling up the Myface site.

"Ok," she said. "So I was going back through Spencer Pines' page yesterday, and I noticed something."

She clicked on three of the fishing photos they had seen before and opened them up side by side.

"What do you see?" she asked.

Dipper and Mabel peered at the screen. In the first picture, Sheldon was wearing a red flannel shirt, standing on a dock, and holding up a small trout. In the second, he was wearing a black t-shirt, sitting in a lawn chair by the side of the lake, and holding a string of three catfish. And in the last, he didn't have any fish, but was sitting in a boat and wearing an 'I'd Rather Be Fishin' shirt.

"I see a guy who likes to fish," Dipper said finally. "But we already knew that – what's the point?"

"Look really close," Wendy urged. "Don't pay attention to what's different – look at what's the same."

Mabel spotted it first. "His hair is exactly the same in every picture!" she exclaimed.

Sure enough, though the outfits and settings were different, Sheldon's brown hair was mussed in the same places in each photo.

"Exactly!" Wendy jabbed a finger at the screen. "He's got hat-head, man – there're a few other shots where he's wearing a ball cap. But he's got the same squished bits in each of these pictures."

"But they're dated months apart!" Dipper protested. "How's that possible?"

Wendy sat back, a satisfied look on her face. "It's not," she said. "Unless the times were faked."

"Can you do that?"

She turned back to the computer and pulled up her own Myface page. "Check this out."

She clicked on the photo that popped up, and showed it to Dipper and Mabel. "Notice anything special?"

"It's the same outfit you're wearing now," Mabel said. "And you have a scratch on your arm – the same scratch."

"That photo is from today," Dipper agreed.

"Precisely." Wendy snapped her fingers at him. "But look – my Myspace timeline says that this was posted more than a year ago. It's the easiest thing ever to backdate a post, man. You just fill out the time and date that you want it to appear. Now, here's the best part."

She went back to Sheldon's page and began to scan through. "Look at the timestamp on each post. They're all only a few minutes apart, even if they're on different days. 12:01, 12:03, 12:07, 12:10. So he made sure to set the date so it looked like everything was posted on different days, but he didn't bother to change the time, so it defaulted to whatever time it was when he actually posted it."

"So this whole thing is a fake?" Dipper stared at the grinning figure of Sheldon on the screen, posing with a soda in the back of a boat.

"It's all fake," Wendy agreed.

"So Sheldon Pines isn't real?" Mabel asked. "But he had a birth certificate."

"Ah-ha!" Wendy shouted.

"Shhh!" the librarian shushed from the front of the library.

Wendy rolled her eyes. "Ah-ha," she repeated in a softer voice. "And _that_ is my final exhibit." She pulled something out of her back pocket and unfolded it.

"Your birth certificate?" Dipper took it, and squinted at the faded print. "Wait – this says your dad's name is George Clooney."

Wendy took the piece of paper back. "That's because it's also fake, man. I whipped it up on my computer last night, printed it out on nice paper, and then roughed it up a bit to make it look old. I did this in like, twenty minutes. With a little more time and better material, you could do _way_ better."

Mabel's eyes were narrow. "Sheldon Pines is a big, stinking, lying, _fraud_ ," she spat out. "And he's got Stan eating out of his hand!"

"The question is, _why_?" Dipper asked. "Wendy, we found a magazine in his stuff that had an article about Gravity Falls." He decided to leave out, for the moment, the author of the article. "We think maybe he's here looking for one of the weird things that turn up in this town."

Wendy sat back and propped her feet up on the computer desk. "Well, he can come to my house," she said. "We've got a pixie infestation in the attic that's driving my dad bonkers."

"I think, if he went to all this work, he's probably looking for something a little bigger than pixies," Dipper said.

He stared at the computer screen, with Sheldon Pines' grinning face staring back at them, almost as if the impostor knew what they were talking about – and was mocking them.

"But what?"


	5. Chapter 5

"Watch out for that squirrel!" Mabel shouted.

Grunkle Stan veered the car sharply to the left, barely missing the brazen rodent. It chittered after them angrily.

Dipper extricated himself from Mabel's yarn, which had come flying over to his side of the car when they swerved. "I could have stayed home and watched the shop," he said. "You don't need both of us to help with groceries."

"Kid, if I let your sister do all the shopping we'd be living on ice cream and Cheesy Doodles all week." Grunkle Stan honked at a jogger.

"A balanced diet is a plate of sweet in one hand and a plate of cheesy in the other," Mabel said piously.

Dipper rolled his eyes. "You stole that from Mom's coffee mug."

She grinned, and started wrapping the long tail of yarn around her hand.

"Besides," Stan added. "I…kinda wanted to get you two alone. To tell you something." He cleared his throat, uncomfortable, and the twins met each other's eyes in sudden concern.

"What is it, Grunkle Stan?" Dipper asked.

"It's…well, it's Sheldon," Stan said. He blew through a stop sign and swerved onto the road that led to the grocery store. "He thinks we should close down the Shack."

" _What?"_ the twin's voices were shrill and unison in their disbelief.

"Grunkle Stan, you can't close the Shack!" Mabel protested.

"Why does he want you to shut it down?" Dipper demanded. "Who is he to say that?"

Stan shrugged. "He thinks it's 'tacky' and 'dishonest.'" He said the words with mocking scorn, but Dipper could hear the uncertainty underneath.

"He's wrong," Dipper declared. "Ok, well… maybe not totally. But it's a tourist trap. It's _supposed_ to be like that."

"That's what _I_ said!" Stan exclaimed. Then, in a quieter voice, he added, "He also said I'm getting to old for this."

The twins gaped. "That's…how could he say that?" Mabel asked. She looked close to tears. Dipper just felt angry – the _nerve_ of that guy!

Stan shook his head. "I know, I know, but – well, he's not wrong. I'm not getting any younger. And maybe it was rude to say it, but Sheldon…well. He's Sheldon."

Mabel and Dipper looked at each other. _Should we tell him_? Mabel mouthed. Dipper shrugged.

"He's not, actually," Mabel said. "He's not Sheldon."

Stan drove in silence for a long moment.

"Wait. What?"

Dipper motioned for Mabel to continue. "He's not Sheldon Pines," she repeated, holding the yarn ball tightly in her lap. "We looked him up online – his whole Myface page is a fake, and we think his birth certificate might be too."

Stan pulled into the grocery store parking lot and slammed to a stop. Turning around in his seat, he met the twins' gazes straight on. "You think I don't know a fraud when I see one?" he demanded. "He's the real deal – he's gotta be."

"Why?" Dipper asked.

Stan looked away. "Because… just _because_ , ok?" He unlatched his seat belt and got out of the car. "I know you don't like him, and I'm not sure about this whole closing-the-Shack business, myself. But that doesn't mean he's a fraud."

He slammed the door and stalked off toward the store, not waiting to see if they would follow.

"That… could have been worse," Mabel said. She sighed and flopped back. "Who am I kidding? That was _terrible_."

"I don't know how we can convince him," Dipper said. He took off his own seatbelt and opened the car door. "And if we can't convince Stan, we're not going to convince anyone."

Mabel followed him out of the car, and they began to walk toward the store, glum.

"Maybe if we can catch him in the act," she suggested. "Like – set up night vision cameras and catch him snooping around the Shack or something."

"We still don't know exactly what he's looking for," Dipper pointed out. "And also I don't think we have any night vision cameras."

"There's so much crazy stuff in Gravity Falls." Mabel stepped in a patch of half-melted tar, leaving a footprint that faded under the hot sun. "He could be after anything – a creature, a person, a hidden trove of scratch-and-sniff stickers…"

Dipper froze.

His sister turned to look at him. "Ok, maybe not the stickers," she admitted. "Besides, they're only hidden under my bed. Not very hard to find. But…Dipper?"

He didn't answer.

"Dipper. Yoo-hoo, earth to Dip-Space-One. Come in, Dip."

"The journal."

"What?" Mabel poked her brother's arm. "Use your words, bro."

"The journal, Mabel. That's gotta be what he's after!" Dipper's hands went to his head, grabbing handfuls of hair in distress. "I left it on my bed! Right out in the open!"

Mabel spun around. "I'll get Grunkle Stan," she shouted. "We'll drive straight home!"

"There's no time!" Dipper whirled and began run, his feet pounding against the hot pavement. "Tell Stan I went home!"

* * *

By the time Dipper reached the Shack, he was sweating, panting, and his legs felt like those fuzzy wire things Mabel was always building stuff out of.

He stopped, just in the shade of the trees around the house, and bent over, gasping for breath.

"Ok, Dipper," he said to himself. "Gotta do this smart." He considered the Shack, watching for any movement.

Nothing.

Sheldon's car was parked out front, but if he was in the building, he was away from windows.

"Ok, so here's what I've gotta do.

"What?

"I've gotta get into the attic without Sheldon spotting us.

"But I don't know where he is."

Dipper stared at the Shack. "Ok, here's what we're going to do.

"Just say it already.

"Well, first: I'm going to stop talking to myself like this. I sound crazy."

A crash sounded from inside the Shack.

"Ok, enough fooling around," Dipper muttered. He pulled his cap down tight on his head. "I'm going in."

He took a deep breath – and sprinted across the clearing around the Shack, slunk up the front porch steps, and plastered his back against the wall by the door, listening.

There wasn't a sound from inside.

Pulling the screen door open – slowly, ever so slowly – he slipped into the house.

The Shack was silent. He knew Sheldon was here somewhere – but for the moment…nothing.

Careful of each creaking board, Dipper tiptoed across the entryway, and up the stairs. He tested each step before moving, holding his breath as he eased his weight up each level.

 _Creeeee—_.

He flinched, freezing in place halfway up the stair. Too far to go back, not far enough to step up the next stair… He'd have to chance it.

 _—eeeeek_.

Dipper winced, but there was no answering sound from Sheldon, either upstairs or down in the main part of the house.

At the top of the stairs, Dipper could see light shining from the open attic door. If he was lucky, he could slip in, grab the journal, and dash out of the Shack before Sheldon even knew he was there.

Finally reaching the top step, Dipper crept along the wall to the open door. He peered around the doorframe – and spotted the red leather of the journal lying safe on his bed.

With a sigh of relief, he stepped into the room, relaxing.

A rough hand grabbed him from behind, clasping over his mouth. Something hard smashed into the back of his head…

And everything went dark.

* * *

 **A/N:**

And this is where it gets a little bit more intense than typical eps usually do... well, unless you count giant heads with arms dragging around town and asking people to please get in their mouths... You know what, I take it back. I got nothin' on Hirsch. :D

I probably won't post next Friday, seeing as it's Christmas and all, but we'll see. I may post a bit early/late or just wait for the next week. If I don't see you until after, Merry Christmas, everyone!

~Essie


	6. Chapter 6

**A/N:** Hey, only a day late, even with holiday craziness! :D I'm going to give a warning/tag here for some mild mentions of blood and trauma, just in case that's something any of my readers are concerned about. And when I say mild I really do mean it, but I've been online long enough to know that sort of warning is appreciated.

Anyway, glad to be back with you all. Only a few more chapters of Pack of Lies left and then we get to move on to something new - no spoilers, but I'm pretty excited about it. :) See you next week!

~Essie

* * *

6.

When Dipper came to, he was in total darkness. His head throbbed. He reached up a hand to touch the aching spot, and winced. Half-dried blood crusted his hair, and a tender spot just above his right ear felt swollen and hot. His fingers came away feeling sticky.

He was lying on his back on a dirt floor, sprawled as if someone had tossed him there. Which…thinking back, they probably had. He tried to remember how he'd gotten there – wherever "there" was.

"Ok," he muttered aloud. "We were on our way to the store…and then I ran home, and… Sheldon." The impostor had ambushed him in the attic. "Ow – what did he hit me with?"

Gingerly, he pushed himself to a sitting position – and nearly threw up. "Ow, ow, ow, ow…" he mumbled, managing to find a wall to his left and supporting himself against it. The wall was dirt too.

"I must be in… a cellar? I didn't know the Shack _had_ a cellar."

The place was pitch black, not a sliver of light anywhere.

"Either that, or I'm blind.

"That's not helping, Dipper.

"Neither is talking to myself." Dipper got his feet under him, and stood. A wave of wooziness swept over him. "Then again…maybe talking is good. Talking means awake. Awake means not unconscious. Not unconscious means getting out of here.

"Great. Talking it is."

He felt around, following the line of the dirt wall until he came to a corner, then following that wall to another corner, and so on until he had made a complete circuit of his prison. Along one wall, he ran into a set of empty shelves – three levels, splintering wood, probably covered in cobwebs and spiders that Dipper couldn't see. He stepped around it, feeling his way along until he met dirt on the other side.

"Ok…six steps long, four wide." He reached up. "Can't touch the ceiling. No door – must be a trap door up there somewhere. What about the floor?"

Wincing at the throbbing in his head, he got down on his knees and crawled around the small space. His seeking fingers found nothing but a long wooden pole – a dowel rod of some kind, abandoned along one wall.

"Well, now I can whack Sheldon if he comes back," he said, finally sitting back down and resting his back against the wall. Dizziness swept over him in waves, rhythmic with his heart beating.

What was he going to do? He yawned, eyelids drooping. He was so tired, and his head hurt so bad… maybe he should sleep – just a nap, just a few minutes, so he'd feel better and could think of a way out of here…

Dipper pushed himself to his feet, swaying. Tears stung his eyes at the sudden wash of pain from the movement, but he didn't sit down again. "Can't sleep," he muttered to himself. "Sleeping and head injuries…not a good combo, Dipper.

"Glad I remembered, dummy," he replied to himself. "Took me long enough."

His voice sounded small and flat in the darkness, but it was better than nothing. "I'm going to drive myself crazy," he said.

"Probably, but then – that hasn't stopped me before.

"I should probably be quiet, though," he pointed out to himself, pacing three steps forward, turning, and pacing three steps back. The motion hurt his head, but it was better than just standing still. "If Sheldon hears me talking, he'll know I'm awake.

"Know I'm not dead, I mean.

"Wait, what?" Dipper froze, but then nodded slowly. "Ow. I mean – right. He…he tried to kill me. He probably thought I was dead – or at least, that I wouldn't wake up. And would be dead soon."

Panic blossomed in his chest. "Oh, no – what if I'm in the middle of the woods somewhere? Or even somewhere outside Gravity Falls? I could have been out for hours!" He'd just assumed he was still in the Shack, but what if he wasn't?

"He…he _actually_ tried to kill me," he repeated, the realization sinking in. Sheldon Pines – or whoever the impostor really was – had really and truly tried to murder him. It wasn't the first time someone – or some _thing_ – had tried to kill Dipper, of course. But it was worse somehow, when it was a member of your own species and not a hoard of hive-mind gnomes or vindictive child prodigies. (Dipper was pretty sure Gideon didn't count as a member of the human species. He was an alien grub of some kind or…something.)

Should he shout for help? If he was still in the Shack, someone might hear him…then again, it might be Sheldon that heard him. Dipper didn't want him to come back and – he swallowed hard – finish the job.

No, he'd have to get out of here on his own.

"Ok, what are our assets?" he asked himself. "Me, myself, and I – and a big lump on my head. And a stick." He felt for the rod again and picked it up, swishing it experimentally. "No ladder, no light, no cell phone…" He started pacing again, tapping the wooden rod against the floor with every step. There was still no sound from above him, and Dipper pushed away the resurging panic about possibly being in an abandoned root cellar in the middle of nowhere. He'd never get out if he allowed himself to panic.

"Think, Dipper. What would Mabel do?

"Probably make something. Knit a ladder, or pull a shovel out of her pocket, or…or something."

His outstretched hand brushed against the rickety shelving unit in the corner, and he flinched back. Visions of hairy spiders and scuttling cockroaches danced in his head.

"Wait!" he exclaimed, "The shelves!

"Why didn't I list that among our assets?" He tugged on the shelf, encouraged when it wobbled. "It's not attached to the wall," he muttered. "If I can figure out where the trap door is…"

Assuming there _was_ a trap door. And that it wasn't locked. And that Sheldon hadn't put something on top of it. But he couldn't afford to think like that.

Carefully, he lifted the dowel rod above his head, thrusting it upward at the unseen ceiling. It bumped against something that gave a little, and a handful of moist dirt sprinkled Dipper's face.

"Ceiling is approximately three feet above my head," he said, continuing his monologue. "Now, if I can just find that trap door."

He began walking a grid – or as close to a grid as he could manage in the complete darkness – stabbing the ceiling above his head with the dowel rod and pretending the little showers of dirt and things that skitter didn't bother him.

 _Thup, thup, thup_ , the dowel said, stabbing into dirt, dirt, and more dirt. Dipper reached the wall and turned back, scooting half a step to his right and starting back toward the other side of the room.

 _Thup, thup, thup_ … Nothing but dirt. Once, he knocked down a stone that thudded to the ground in front of him. Dipper reached down and felt for it – the rock was nearly the size of his fist.

"Lucky that didn't hit my head," he said. His skull felt like it was being squeezed in a vise, blood pounding through constricted veins. He certainly didn't need another head injury.

 _Thup, thup, thup._

 _Thup, thup, thup._

 _Thup, thup_ – _THUNK._

Dipper froze, arms stretched above him, gripping the wooden rod tightly. He poked again, and was rewarded by the sound of wood meeting wood. _Thunk_.

"I found it," he whispered. Suddenly, he was afraid of someone – of Sheldon – hearing him. As quietly as he could, he stabbed the dowel into the dirt floor at his feet, driving it down as a marker. Then he felt his way to the wall and followed it until he met the rickety shelving unit.

Grasping its sides, he pulled it away from the wall and began to drag the clumsy contraption toward his marker and the trap door. Splinters bit at his fingers, and more than once he felt as though something small and hairy had run over his knuckles. It weighed more than he'd expected – it had a solid back and sides, more like a bookshelf than just a set of boards nailed together for basement storage. Inch by rattling inch, he moved the shelves away from the wall and into the center of the room.

When he reached the place he'd marked with the dowel, he stopped and listened.

Still no noise from above. If he was under the Shack, Sheldon was either away from the place or gone entirely. If he wasn't under the Shack…well, he'd deal with that when he had to.

A new wave of dizziness swept over him, and when he gingerly touched the place where he'd been hit, his hand came away wet.

"I gotta get out of here," he mumbled, supporting himself against the shelves. He grabbed the dowel and yanked it out of the ground.

Grabbing onto the top shelf, he pulled himself up, using the shelves as a makeshift ladder. When he reached the top, he scooted onto the highest shelf – extremely aware of how much the old unit wobbled under his weight – and reached above his head.

His fingers encountered smooth wood – and an old fashioned, round, metal handle. Trembling, he turned the latch and pushed.

The trap door creaked open, and yellow light slashed across Dipper's vision. He winced, eyes watering, and peered out.

He was in the living room of the Mystery Shack – and Sheldon Pines was sitting in Grunkle Stan's chair, staring at him.


	7. Chapter 7

Dipper jerked back, letting the trap door slam shut above him and nearly falling when the shelves rocked to one side.

Sheldon was still there! Waiting for him!

Footsteps crossed the floor above Dipper's head, and the trap door flew open. A strong hand – stronger than it looked – grabbed him by the arm and hauled him out of the dank prison cellar and into the late afternoon light that flooded through the living room window.

"I really don't like having to do this, I hope you know," Sheldon grunted, throwing him to the floor. He loomed over Dipper, suddenly far more intimidating than the all-around-generic man the twins had first met. "But what I'm after is too important. I can't let you stop me."

Dipper scuttled back, his fingers questing for something – anything – to use as a weapon. "Who are you, anyway?" he demanded, stalling for time. "What do you want?"

"I want the threshold," Sheldon snarled. He grabbed a lamp from the end table and snapped the cord from its base. Throwing aside the broken lamp, he wrapped the ends of the cord around his hands. "I know it's here – somewhere. That uncle of yours can act the idiot all he wants, but it's here _somewhere_ and I know he knows where it is."

"What are you talking about?" Dipper's eyes were locked on the cord in Sheldon's hands. It looked uncomfortably like a garrote.

Sheldon lunged for Dipper, who managed to duck to the side and scramble halfway to his feet, stumbling toward the doorway.

"Not so fast!" Sheldon kicked Dipper's feet out from under him. "You're not getting away – I'm sorry kid, but I don't have a choice."

Dipper rolled onto his back, staring up at the man who was going to kill him. There was a mad light in Sheldon's eyes.

"You'd understand if you knew," the man said. His gaze was sharp, piercing. "The power the threshold could produce! The mysteries it could unlock – and your uncle is hiding it!"

"Grunkle Stan doesn't know anything about a threshold or whatever!" Dipper protested, pushing himself back, scooting along the floorboards. "We saw the article in your bag – but that's not Stan! He couldn't have written that!"

"Yes, he _did_ ," Sheldon growled. He gripped the cord, his knuckles whitening. "Stanford Pines, scientific researcher into the strange and unknown. He wrote three articles on the potential of an interdimensional portal and—"

He lunged, and caught Dipper, wrapping the lamp cord around Dipper's throat.

Dipper choked, his airway suddenly cut off. He flailed at Sheldon, but the man held grimly on, pulling the garrote tighter.

All Dipper knew, in that moment, was that there should be air coming into his body, and there _wasn't_. Every part of him rebelled – feet kicking, fists flying, eyes bulging – to no avail. Sheldon was bigger, heavier, stronger. No twelve-year-old boy could win against this.

There was a wheezing sound, a terrible, gasping, sputtering, rasping sound, and it was _him_ , Dipper realized. It was the horrible sound of something dying, and he _had to fight back_.

Bucking wildly, he managed to throw Sheldon off balance. The pressure to his neck eased slightly, and Dipper gasped in a ragged breath of air that burned down his throat. He tried to scrabble back, to get further away, but Sheldon had already recovered.

"Stupid _brat_ ," the man gritted, his eyes dark with hatred and insanity.

" _Grappling hook!_ "

Something flew through the air and conked Sheldon on the side of the head. He froze, his face suddenly dull.

 _Mabel,_ Dipper thought, his vision going dim and fuzzy around the edges.

 _"Get off my nephew!"_ Grunkle Stan roared, and suddenly there was no Sheldon on top of Dipper, and the cord around his neck had no strength behind it. And then Mabel was there, grabbing her brother by the shoulder and there were tears in her eyes and a look of fury on her face, and she helped Dipper to his feet in time to see Grunkle Stan land a solid punch on Sheldon's jaw –

And the kidnapping impostor dropped to the floor. Out cold.

Dipper sagged against his sister, weakly tugging the cord away from his throat. Mabel wasn't talking, which struck him as unusual, until he actually tore his eyes away from Sheldon's unconscious form and looked at his sister.

The level of fury and righteous, avenging wrath in his twin's face was enough to startle him out of his lethargy.

"Hey," he said, grabbing her arm. "Hey – it's ok. I'm ok."

"I'm going to _shred_ —I'm going to _rip him to bits_ —I'm going to…" Mabel's voice was low and growling, and her breath came in little huffing pants, like an angry bull. She wasn't looking at him, her gaze fixed on the insensible Sheldon. Grunkle Stan was wrapping the man's wrists in duct tape.

"Mabel," Dipper rasped. "It's _over_." He tugged her arm. "Hey, look at me."

She finally looked at him.

"I'm ok," Dipper said. He coughed and rubbed at his neck. "Well. Mostly."

Mabel blinked, and the anger faded away. She was his sister again — not some avenging creature of doom — and her whole body relaxed. She snuffled back tears and held up the grappling gun in her hand.

"Grappling hook," she whispered.

Dipper laughed – it hurt his raw throat, and he broke into a coughing fit halfway through, but he laughed.

"Grappling hook," he repeated. "Always with the grappling hook."

* * *

They called the police, who showed up and carted Sheldon – now awake and vowing incoherent revenge on all and sundry – off to the county lockup.

"His name's actually Frederick Hansen," Sheriff Blubs told them. Dipper had to give a statement, and might have to testify eventually, but that was off in the far distant future.

Like, November.

"He's a down-and-out scientist from Miami with a record of petty crimes – vagrancy, public drunkenness, plagiarism of scientific articles, attempted mass extermination of lab mice… We're not sure what brought him to Gravity Falls, though." He narrowed his eyes at Dipper. At least, that's what Dipper thought he was doing behind those dark sunglasses. "You wouldn't have any ideas, would you?"

"Hey," Grunkle Stan said. "Lay off the kid. He's been through a _traumatic experience_." He said the last two words like they were a magic spell – and they might as well have been. Blubs sat back in his chair and shuffled some papers together.

"Anyway," he said, "We're shipping him upstate to the big boys at the capital. They'll be bringing charges of fraud, forgery, kidnapping and attempted murder so… You may be getting a few calls here in a week or two." He lowered his glasses and peered at Dipper over the lenses. "You're a very lucky boy, City Boy."

Dipper nudged Mabel, who elbowed him back – hard. "Ow. I mean – yeah. I know."

They left the police station and headed back to the Shack. Dipper had spent most of the morning in the hospital, getting various cuts and bruises seen to. He had a concussion and a bruised trachea, but the doctors also told him he was very lucky.

"I don't think I'm that lucky," he muttered to Mabel, sitting in the back seat of Grunkle Stan's car. He grinned at her. "I think I just have a sister with good aim and a grunkle with a strong left hook."

She laughed, and – to his surprise – reached over and gave him a fierce (if somewhat awkwardly-sideways) hug. "Don't do that to me, _ever_ again," she ordered. "Promise?"

He hugged her back. "I promise."

Stan glanced at them in the rearview mirror. "So, ah…" he said, gripping the steering wheel tightly. "I hear there was a, um… a bit of confusion about some sciency-nerdy article thing?"

The twins looked at each other.

"Grunkle Stan, Sheldon-Not-Sheldon-Frederick had an article on dimensional science stuff," Mabel said. "It sounded like it might have been about Gravity Falls, and… it had your name on it."

"Yeah, and then, when he was attacking me, he said something about two other articles," Dipper added. "He called you 'Stanford Pines, scientific researcher into the strange and unknown.'"

Grunkle Stan looked extremely uncomfortable. "Well, uh… ya see, it's like this. Um…" His gaze flickered between their reflection in his rearview mirror and the road in front of him. "I…"

"You what?"

"I..." Stan clenched his hands on the steering wheel. "I...I stole the article."

"What?" the twins chorused.

"Ah, yeah," Grunkle Stan's voice was brash – the surest sign he was feeling guilty. "I stole it. That's the truth. There was this old coot who came through when I first started up the Mystery Shack – it was the Murder Hut back then. He had a bunch of papers he tried to give me, tried to convince me there was something wacky about the place… I didn't believe him, but I…well, I may have sent a few of the articles off to some nerdy science magazine and gotten twenty bucks for them. Each," he added, as if it were an important detail.

Dipper felt a surge of disappointment. "You mean, you didn't write them?"

"Kid, I can barely keep track of the Shack's budget. You think I wrote all that science crap? Puh-leez." Stan rolled his eyes and barked out a laugh.

Dipper and Mabel looked at each other, and Dipper sighed. "Yeah, that makes sense." He guessed it would have been too much to hope that his great uncle Stanford was the mysterious author of the journals. But maybe…

"What happened to the guy who gave you the papers?" he asked Stan.

Stan shrugged. "No idea. He disappeared the next morning and I never saw him again. Probably eaten by a were-badger or something."

 _Or maybe,_ Dipper thought, fingering a bandage on his elbow, _Maybe he disappeared into the woods, built that bunker, and wrote the journals!_

He fell back against the seat. "We've got to call Wendy," he said. "After all, she's the one who proved Sheldon wasn't Sheldon."

Grunkle Stan's shoulders sagged a little. "Yeah," he said. "Looks like there never was a Sheldon Pines. Or a Debbie."

The twins exchanged glances.

"It's ok, Grunkle Stan," Mabel said, leaning forward. "You've still got us."

A smile crept over Stan's craggy features. "Yeah," he agreed. "Family's great, right?"

He drove in silence for a minute. Then,

"…By the way, Dipper, don't think this head injury's gonna get you out of shop duty."

 ** _FIN_**

* * *

The End. :D

This one was so much fun to write — even though I still think Sheldon-Not-Sheldon-Frederick attacking Dipper was a little OOC for this show. But... It worked.

Anyway.

For anyone who's curious, I'd like to say here that I blatantly stole the basic idea for this story from a kid's book called _A Stranger, a Thief, and a Pack of Lies_ , by Chris Auer. My little brother had it lying around the house and I loved the idea of an impostor in the Shack – also, the scene at the end where the main character has a conversation with himself was too good to pass up. (Though I will say that it was hard to write that "conversation" without sounding like a certain dorito was involved, so sorry if anyone got confused there at all.) Anyway, credit where credit is due and all that. :) Thanks for reading! The next adventure fic shall be starting soon:

 _"There were three things in life that Mabel Pines hated._

 _Baby dragons wasn't on the list."_

Leave a comment, and have a great day!

~Essie


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